nsc_gpio.c 3.5 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /* linux/drivers/char/nsc_gpio.c
  3. National Semiconductor common GPIO device-file/VFS methods.
  4. Allows a user space process to control the GPIO pins.
  5. Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
  6. Copyright (c) 2005 Jim Cromie <jim.cromie@gmail.com>
  7. */
  8. #include <linux/fs.h>
  9. #include <linux/module.h>
  10. #include <linux/errno.h>
  11. #include <linux/kernel.h>
  12. #include <linux/init.h>
  13. #include <linux/nsc_gpio.h>
  14. #include <linux/platform_device.h>
  15. #include <linux/uaccess.h>
  16. #include <asm/io.h>
  17. #define NAME "nsc_gpio"
  18. void nsc_gpio_dump(struct nsc_gpio_ops *amp, unsigned index)
  19. {
  20. /* retrieve current config w/o changing it */
  21. u32 config = amp->gpio_config(index, ~0, 0);
  22. /* user requested via 'v' command, so its INFO */
  23. dev_info(amp->dev, "io%02u: 0x%04x %s %s %s %s %s %s %s\tio:%d/%d\n",
  24. index, config,
  25. (config & 1) ? "OE" : "TS", /* output-enabled/tristate */
  26. (config & 2) ? "PP" : "OD", /* push pull / open drain */
  27. (config & 4) ? "PUE" : "PUD", /* pull up enabled/disabled */
  28. (config & 8) ? "LOCKED" : "", /* locked / unlocked */
  29. (config & 16) ? "LEVEL" : "EDGE",/* level/edge input */
  30. (config & 32) ? "HI" : "LO", /* trigger on rise/fall edge */
  31. (config & 64) ? "DEBOUNCE" : "", /* debounce */
  32. amp->gpio_get(index), amp->gpio_current(index));
  33. }
  34. ssize_t nsc_gpio_write(struct file *file, const char __user *data,
  35. size_t len, loff_t *ppos)
  36. {
  37. unsigned m = iminor(file_inode(file));
  38. struct nsc_gpio_ops *amp = file->private_data;
  39. struct device *dev = amp->dev;
  40. size_t i;
  41. int err = 0;
  42. for (i = 0; i < len; ++i) {
  43. char c;
  44. if (get_user(c, data + i))
  45. return -EFAULT;
  46. switch (c) {
  47. case '0':
  48. amp->gpio_set(m, 0);
  49. break;
  50. case '1':
  51. amp->gpio_set(m, 1);
  52. break;
  53. case 'O':
  54. dev_dbg(dev, "GPIO%d output enabled\n", m);
  55. amp->gpio_config(m, ~1, 1);
  56. break;
  57. case 'o':
  58. dev_dbg(dev, "GPIO%d output disabled\n", m);
  59. amp->gpio_config(m, ~1, 0);
  60. break;
  61. case 'T':
  62. dev_dbg(dev, "GPIO%d output is push pull\n", m);
  63. amp->gpio_config(m, ~2, 2);
  64. break;
  65. case 't':
  66. dev_dbg(dev, "GPIO%d output is open drain\n", m);
  67. amp->gpio_config(m, ~2, 0);
  68. break;
  69. case 'P':
  70. dev_dbg(dev, "GPIO%d pull up enabled\n", m);
  71. amp->gpio_config(m, ~4, 4);
  72. break;
  73. case 'p':
  74. dev_dbg(dev, "GPIO%d pull up disabled\n", m);
  75. amp->gpio_config(m, ~4, 0);
  76. break;
  77. case 'v':
  78. /* View Current pin settings */
  79. amp->gpio_dump(amp, m);
  80. break;
  81. case '\n':
  82. /* end of settings string, do nothing */
  83. break;
  84. default:
  85. dev_err(dev, "io%2d bad setting: chr<0x%2x>\n",
  86. m, (int)c);
  87. err++;
  88. }
  89. }
  90. if (err)
  91. return -EINVAL; /* full string handled, report error */
  92. return len;
  93. }
  94. ssize_t nsc_gpio_read(struct file *file, char __user * buf,
  95. size_t len, loff_t * ppos)
  96. {
  97. unsigned m = iminor(file_inode(file));
  98. int value;
  99. struct nsc_gpio_ops *amp = file->private_data;
  100. value = amp->gpio_get(m);
  101. if (put_user(value ? '1' : '0', buf))
  102. return -EFAULT;
  103. return 1;
  104. }
  105. /* common file-ops routines for both scx200_gpio and pc87360_gpio */
  106. EXPORT_SYMBOL(nsc_gpio_write);
  107. EXPORT_SYMBOL(nsc_gpio_read);
  108. EXPORT_SYMBOL(nsc_gpio_dump);
  109. static int __init nsc_gpio_init(void)
  110. {
  111. printk(KERN_DEBUG NAME " initializing\n");
  112. return 0;
  113. }
  114. static void __exit nsc_gpio_cleanup(void)
  115. {
  116. printk(KERN_DEBUG NAME " cleanup\n");
  117. }
  118. module_init(nsc_gpio_init);
  119. module_exit(nsc_gpio_cleanup);
  120. MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>");
  121. MODULE_DESCRIPTION("NatSemi GPIO Common Methods");
  122. MODULE_LICENSE("GPL");